| 摘要 |
<p>A particulate insulating material is disclosed which includes a sound absorptive central core having a density of at least 1.0 grams/cm3, and an outer less dense thermally insulating coating provided at least partially about the core. The outer coating is selected to provide thermally insulating properties and may have either an open or closed foamed or expanded cellular structure and a density of less than 0.75 grams/cm3, with the core comprising between about 5 to 80% of the granule by volume. The high density core is chosen from a material which absorbs, reflects and/or diffracts sound waves, such as metals as well as natural and synthetic solid compositions and compounds.</p> |
